Data Processing Device for Use in an Ad-Hoc Network, and Corresponding Ad-Hoc Network

1. A data processing device having a processor connected to memory to run software applications stored on the memory and a data interface for use in an ad-hoc network, comprising: an application stored in the memory for processing a first information, the application configured to access a central service via the data interface to transmit data to the central service and receive data from the central service; and a representative entity connected to the application via the data interface for exchanging the first information, the representative entity configured to connect to a plurality of further data processing devices via data links for exchanging a second information via the ad-hoc network, the representative entity adapted to form the first information from the second information and to form the second information from the first information; the representative entity: configured to determine if the central service is available, configured to determine whether a desired receiver of the first information is a user of a further data processing device available via the ad-hoc network if the representative entity determines that the central service is unavailable, and configured to forward the second information to the further data processing device of the desired receiver if the representative entity determines that the desired receiver is available via a further data processing device in the ad-hoc network.

2. The data processing device according to claim 1 , wherein the central service is a service for electronic messages provided by a central server and wherein the first information is at least one electronic message.

3. The data processing device according to claim 2 , wherein the at least one electronic message has address information of the further data processing device of the desired receiver and the representative entity is configured to effect the forwarding of the at least one electronic message as second information to the further data processing device available at the address information.

4. The data processing device according to claim 2 , wherein the representative entity is adapted to buffer-store the at least one electronic message to be forwarded or exchanged if the representative entity determines that the central service is unavailable and the further data processing device of the desired receiver is not available.

5. The data processing device according to claim 2 , wherein the representative entity is adapted to process e-mail messages, appointment elements or calendar entries as the at least one electronic message.

6. The data processing device according to claim 1 , wherein the application is configured to access a resource, and wherein at least one of the data links allows the resource to be used by at least one of the further data processing devices.

7. The data processing device according to claim 6 , wherein the representative entity is provided with an authorization apparatus adapted to enable or disable the resource.

8. The data processing device according to claim 6 , wherein the resource is a printer or a network access point.

9. The data processing device according to claim 8 , wherein the data processing device is a computer, a PDA or a phone.

10. The data processing device according to claim 1 , wherein the application is adapted such that the data processing device is able to process presence information from at least one of the further data processing devices, and wherein the representative entity is set up to receive the presence information as second information via at least one of the data links from at least one of the further data processing devices and to forward the presence information as first information to the application.

11. The data processing device according to claim 10 , wherein the application is set up to exchange the presence information as first information based on a SIP protocol, and wherein the representative entity includes an SIP presence registration function and an SIP presence server function.

12. The data processing device according to claim 11 , wherein the application is adapted to generate presence information about the data processing device or of a user of the data processing device as first information, and wherein the representative entity is set up to send the generated presence information as second information via at least one of the data links to at least one of the further data processing devices.

13. The data processing device according to claim 1 , wherein the application is adapted to generate presence information about the data processing device or of a user of the data processing device as first information, and wherein the representative entity is set up to send the generated presence information as second information via at least one of the data links to at least one of the further data processing devices.

14. The data processing device according to claim 1 , wherein the application comprises a display function or a processing function for addresses, and wherein the representative entity is adapted to transmit an address of at least one of the further data processing devices in first information to the application.

15. The data processing device according to claim 14 , wherein the representative entity is set up to retrieve the address to be transmitted to the application as second information from the at least one further data processing device.

16. The data processing device according to claim 14 , wherein the application is a display and processing program for electronic messages that is stored in the memory and run by the processor, and the address can be used to send electronic messages.

17. An ad-hoc communication network, comprising: a plurality of processing devices, each data processing device having at least one processor, memory, and at least one data interface, each data processing device comprising: an application for processing a first information, the application configured to access a central service via the at least one data interface to transmit data to the central service and receive data from the central service, and a representative entity connected to the application via a first data link for exchanging the first information, the representative entity connected to other data processing devices of the plurality of data processing devices via second data links for exchanging a second information via the ad-hoc network, the representative entity adapted to form the first information from the second information and to form the second information from the first information, and the representative entity: configured to determine if the central service is available, configured to determine whether a desired receiver of the first information is a user of a further data processing device available via the ad-hoc network if the representative entity determines that the central service is unavailable, and configured to forward the second information to the further data processing device of the desired receiver if the representative entity determines that the desired receiver is available via a further data processing device in the ad-hoc network.

18. An ad-hoc communication network according to claim 17 , wherein the plurality of data processing devices is comprised of a first data processing device and a second data processing device, the application of the second data processing device adapted to exchange information with the representative entity of the first data processing device.

19. An ad-hoc communication network according to claim 17 , wherein the plurality of data processing devices is comprised of a first data processing device and a second data processing device, the application of the first data processing device set up to exchange the information using the representative entity of the first data processing device.

20. An ad-hoc communication network according to claim 19 , wherein the application of the second data processing device is adapted to exchange information with the representative entity of the first data processing device.

21. The ad-hoc communication network of claim 20 wherein each of the data processing devices is a computer, a PDA or a phone.